Hiya,
I have noticed significant changes, during the last few days my pageranks were changing up and down from 5 to 6 at different times of the day... the homepage has now settled at 5 but significant changes and benefits to pages within my site, many pages which previosly had
PR of 0,2,3... all now with 4 or 5 - may be more luck than judgement but Im happy getting the extra 3-400 unique visitors a day and growing.